The present invention relates to an electrolyzing device for electrolyzing treated water in terms of an electrochemical method, and more particularly, to an electrolyzing device capable of efficiently removing scales adhered to an electrode forming a cathode when a tap water corresponds to the treated water.
In the past, there is known an ionized water forming device for forming alkaline ionized water or acid ionized water by electrolyzing water in such a manner that at least a pair of electrodes is immersed in the water, a barrier membrane is provided therebetween, and electric current flows between the electrodes (for example, see Japanese Patent Application Laid-Open No. H06-165985). Besides, there is known an electrolyzing device for forming hypochlorous acid, ozone, etc. in treated water by treating a tap water as the treated water containing at least chloride ion in terms of an electrochemical method, for example, in such a manner that at least a pair of electrodes is immersed in the water and electric current flows between the electrodes to perform an electrolyzing treatment (for example, see Japanese Patent Application Laid-Open No. 2003-24943).
Since calcium ion or magnesium ion is contained in the electrolyzed tap water, scales mainly containing the calcium or the magnesium are adhered to a surface of an electrode forming a cathode while electric current flows between the electrodes. When the precipitation of the scales grows, the surface of the electrode forming the cathode is covered with the scales, and an area functioning as the electrode becomes narrow, thereby causing a problem in that electrolyzing efficiency deteriorates. Then, when the electrodes are adjacently arranged, a flow passage is blocked due to a lamination of the scales formed between the electrodes, thereby causing a problem in that it is difficult to form electrolyzed water.
Therefore, in general, the scales adhered to the electrode are removed by changing the polarity of the electrode whenever the electrolyzing treatment is carried out for a predetermined time.
Meanwhile, as an electrode used for the electrolyzed water forming device, electrodes exhibiting various functions have been developed. For example, as an electrode having a large ozone forming potential, electrodes of which a surface functioning as a catalyst mainly contains dielectric material such as tantalum oxide have been developed. The electrolyzed water forming device performs an electrochemical treatment to the tap water as the treated water by applying a positive potential to one electrode and applying a negative potential to the other electrode made of insoluble metal. Accordingly, ozone is high-efficiently formed by the electrode having a surface layer functioning as a catalyst, that is, the anode.
However, in this case, when the scales of the insoluble electrode forming the cathode are removed by changing the polarity, the electrode having the surface layer functioning as the catalyst is changed to the cathode. Accordingly, the surface layer mainly containing the dielectric material is destroyed and broken, and the surface layer is apparently separated. For this reason, the durability of the electrode having the surface layer apparently reduces, thereby causing a problem in that an ozone forming function during a general electrolyzation apparently reduces.
Accordingly, it is necessary to remove the scales adhered to the surface of the other electrode during the electrolyzation without using the electrode as the cathode. As such a method, it may be supposed that an acid cleaning is carried out by using a medical agent or a physical scale removal is carried out. However, in this case, a problem arises in that a medical agent management or system becomes complex.